


Undertale : Two Hearts Remake ( War of Mercy and Genocide series)

by LolipopPanda



Series: Undertale Mercy and Genocide Series [2]
Category: Undertale
Genre: F/M
Language: English
Status: In-Progress
Published: 2018-08-23
Updated: 2019-05-19
Packaged: 2019-07-01 07:19:28
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 4
Words: 4,452
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15769275
Author URL: https://archiveofourown.org/users/LolipopPanda/pseuds/LolipopPanda
Summary: Laney and Sally are both best friends and Laney knows very little about her younger sister's history. Or why her younger sister Frisk disappeared . Now both Laney and Sally find that they have fallen into a underground world of monsters. What adventures lies ahead of them? And how does a certain blue hoodie skeleton know Frisk?





	1. A New Tale Begins

**Author's Note:**

> Hey guys what's up this fic is the alternate universe of Undertale. So some of the stuff might be slightly different from the game but still to the story line. So I really really hope that you will enjoy this fic.  
> Warning: Fluff, abuse, violence, some drug use ,spoliers for both sides of the game,and bad bad verbal language.  
> Thank you for trying it out.  
> love you all,  
> Lilmewpanda  
> Ps. Future San was inspired by Undertale Aftertale on youtube awesome comic dub you should check it out on youtube. Lastly this is only fic one of my Mercy and Genocide series.

It was a beautiful day outside the birds singing, the flowers were blooming, as the sun was shining.

Yup, a beautiful day indeed but uh for some humans it wasn't such a beautiful day. It was more like a day in hell those two humans that I'm talkin' about was Frisk and her older sister Laney.

Their day was goin' so well that was until their asshole of a father came home drunk as hell.

That was when their day had become a nightmare.

As the asshole made his way towards Frisk. Laney had tried ta' step in the way to stop him. Only to be punched in the face causing her to fall on to the caperted flooring. He then grabbed ahold of Frisk and started to drag her to his bedroom.

Not noticing that Lanes had stood up from the ground and pick up the lamp that was sittin' on the side table next to the couch.

Laney then quickly bashed him in the back of the head with the heavy glass object.

Once their shit head of a father fell to the ground unconscious Laney quickly grabs ahold of her younger sister's hand. And runs out of the house while texting her best friend Sally to meet them in the woods at their usual spot.

As Frisk and Laney arrived at the woods they found a short girl about Lane's height with dark brown hair tied into a high ponytail and soft brown eyes that were filled with worry,

" I got your message. What happen?" Sal asked as she rushes towards Laney who was now nervously twirling a light brown braided pigtail around her finger while shutting her soft blue eyes. As Frisk looks up at her and gives her hand a gentle squeeze.

Laney slowly opens her eyes and gives her younger sister a sweet smile before looking back up towards Sally.

" H-he tried to take Frisk to his bedroom I-I stopped him by hitting him in the back of the head with a lamp." Lanes stuttered as tears filled her eyes.

"...Lanes come to live with me both of you. My dad and I can..."

" We can't he'll know where we are and even if you and your father do something about him. He would only find a way to escape and find his way around the both of you to harm Frisk and me."Laney finishes with a soft sigh.

Only to feel a small tug on her shelve.

Laney looks down towards her younger sister who was now staring back up at her.

" What's up Frisket?" She asked with a small head tilt.

* I know where to go follow me.* Frisk quickly signs as she starts runnin' deeper into the woods.

" Frisk Wait!" Lanes shouted as she and Sal chase after the kiddo.

They both came to a full stop as Frisk jumps down into a deep hole.

After a few minutes of silence, Lanes slowly makes her way towards the hole once she was at the edge Laney prepares herself to jump only to be stopped by Sally who had quickly grabbed ahold of her arm.

"Lanes are you crazy?" Sally hissed while narrowing her soft brown eyes.

" Sal I have to. That's my younger sister down there I have to make sure that she is at least okay...please Sally." the short pigtail girl pleaded to her ponytail friend.

Sally let's out a small sigh of defeat as much as she hated to admit it. Laney had a point that was her younger sister down there. she then lets out annoyed groan as she let's go of Lane's arm and grabs ahold of her hand instead.

" Fine but we're jumping together on the count of three. Ready?" She asked earning a small head nod from her best friend.

" Okay, 1, 2.." once Sal had said the number three both of the girls jumped into the hole hand in hand.

What the girls didn't know was that Frisk had fallen down that hole before.

Only to end up very badly for her and me. I guess the kiddo was hoping that with Laney there it would end the deadly cycle. In a way Frisk was right. Heh, it had also brought my Soulmate to me.

And yet it had also ended up turning into a war. Bringing two friends to fight each other.

And that war was called The War of Mercy and Genocide.


	2. Chapter 1. The Dream

**Summary for the Chapter:**

> Sans Meets another him during his nap and finds out something interesting about our dear reader.

Every Reset starts the same I always wake up to the sounds of Paps yelling at me.

Tellin' me to stop bein' such a lazy bone and then I would go to my station afterwards just to make him happy. After my watch duties I would head to the Ruins to meet a certain kiddo that I had promised to protect.

Even though it feels more like a lie than a promise.

Since every reset now was becoming nothing but a massacre . And I was always the last one, having to see my own brother's death over and over again. It was nothing but a nightmare that kept on repeatin' and repeatin' over and over again never stoppin'. It was drivin' me CrAzY.

Anyways back to our story or uh~ heh, history lesson.

As I said it started like every reset, Paps yellin' at me and me goin' to my station before going to the ruins to meet the kiddo.

But this time it was actually different...This time I had actually fallen asleep.

"Ey', Ey' wake up pal." A deep voice called out to me.

I slowly open my eye sockets finding another me staring down at me with Frisk..or a Frisk hiding behind him.

"What the?!"

" Don't even think about it buddy." the other me said with his one left eye glowing.

" Why are you protecting em'? They killed Paps." I said with low growl only to earn a small shake of his head.

" Correction, Chara did."

" Chara?"

" It's the demon who's been processing Frisk. At first, the kiddo thought that they were some sadden and lonely spirit so she let them come along with them on every adventure. Yes, it was the Frisk's fault for the first genocide run but that was why she had reset to make it right. But~ with her allowing that demonic brat to stay within her soul it weakened. Allowing it to be easier for Chara to take over. The more resets happen the weaker your Frisk's is becoming and yet you can still save her along with Paps and the others."

"And how can I do that?" I asked now calming down as Frisk slowly makes their way towards me.

* That's where I come in. * They signed with a small sad smile.

Now there's something you should know. In everytime line, there's a different Frisk. Some Female, Male, and some preferred to be mentioned as none-gender, along with being different ages. This Frisk preferred to be none - gender and they were the same age as my Frisk.

* ... You will need to work with my sister Laney.*

"....Laney?" I asked now looking slightly confused as Frisk slowly nods their head.

" I got this kiddo it's a long story to sign I don't want your hands to ache later." the other me said as he gently squeezes Frisk's hands while patting their head with his free one.

Frisk looks over at me as I open up my arms with a lazy smile as a peaceful invitation if they were anything like my Frisk they were a big cuddler.

With a small squeak of excitement Frisk rushes over to me and cuddles in my arms as they sit in my lap.

Earning a small chuckle from the other me as he sits down across from us.

" So it started like every reset. Wake up ta' Paps and all that good stuff but there was somethin' different. This time I went ta' the ruins and Tori was waitin' for me outside with Frisket who now had hope in their eyes. She introduced me to Frisk and then apologize for there were two more children of er's that she wanted me to protect. Sally was okay I was still nervous around her but when Lanes was introduced to me... For some reason, my soul was calmed. I don't know if it was that sweet smile of hers or her eyes but I do know it was mostly because of her soul."

"And~ what was er' soul?" I asked thinkin' that it would be the usual ones.

"...Devotion," he responded earning a surprised look from me.

Let me explain ere' there are more souls out there than the ones we know about and among those is the rarest one. Devotion.

It was Determination's twin but softer, gentler, and loyal which also explain the soft pastel pink color that it was.

It was only seen once a long time ago this would be the second time a soul like that was found.

"So~ as I was sayin' after meetin' Frisk, Sal, and Laney I took em' back to my place everthin' was goin' great. Sal had a job even though she was a brat at times it was still nice havin' er' around, Lanes and I have become....close to where we...know what? Nevermind I think you should find that out for your self. But yeah everything was going amazin' and then Chara finally took ahold of Frisk's soul and attack. We won and saved Frisk but not without a sacrifice. This of course had caused a huge argument between me and Lanes. I... I left her by herself.., the biggest regret I had ever made. I came back after clearin' my skull. But when I came back to apologize for saying such cold words to er' I found Laney badly bleeding on the floor with that Demon Brat's new puppet standing over her laughing knife in hand. And Frisk was in the corner of the room badly injured tryin' to crawl their way to their older sister. I was so pissed off that I blindly attack only to miss the brat causin' me to run out of energy. I knelt down by Frisk who had finally passed out from the pain. Chara's new puppet had made another attack which was blocked by a barrier of soft pink butterflies that was healing both Frisk and I. I look over towards Laney who was giving me a weak smile as the reset button dimly sits in front of her. Somthin' else ya' need to know like the kid Lanesters could reset and save as well. The big difference was that like you and I she hated resets. She would only do it if it was becoming out of hand and that the moment it was way~ out of hand. But uh~ the thing was she was to weak and injured to even use her magic. The consequences of her resetting are that the reset won't be complete and we'll be stuck somewhere in the void or Laney would be killed. Tibia honest I was more worried about Laney's death then being stuck in the void. I beg her not to do it but she just shakes her head and asked me to keep Frisk safe along with... telling me her true feelings. After that, she pressed the reset button. As expected Frisk and I had ended up in the void luckily we both were fully healed as for Chara well she has a really rare chance in finding us. The void is a pretty big place after all."

"And what about your Laney?" I asked with a small tilt of my head.

" Is she..?" I stopped as I watch the other me slowly shake his head.

" I don't think Lanes is dead I can still sense her soul it's very faint but she's most likely stuck in the void with us somewhere. The kid and I are still searching for er'. I just wanted ta' stop by with Frisk ere' to give you some advice."

"And that is?"

" You promise that you protect er' with everythin' you have."

"..."

"Yeah, yeah I know we both hate makin' promises but trust me this one is worth it." he finishes with a wink only to have me let out a sigh as I give him a small lazy shrug.

"Sure thing. Can't say no to myself now can I?" I asked with a small wink.

"Thanks, pal. oh and ere'," he added while holding a black string necklace that had a red ruby heart attached to towards me as his Frisk stands from my lap and stands right next to him again.

"What's this?"

" Nothin' much just a necklace that will allow you a tempory soul bond with her trust me it'll help you out a lot. Just~ make sure that you'll give it ta' er' when you're ready." he responded while dropping the necklace into my out strecht hand.

"Wait, W-what?"

" Heh, would you look at the time. You're late for a very special meetin' bud maybe you should wake up. " The other me finishes with a snap of his fingers.

I quickly sit up straight with my eyes sockets now wide open.

As I look at my surroundings I find myself in Snowdin at my station that I had fallen asleep at. I then look down where I find the red ruby heart necklace sitting in front on my bony hand on my station's counter.

" Guess it wasn't just some weird dream after all," I mumble under my breath as I pick up the necklace while leaving the station and making my way towards the ruins.

"...Temporary soul bond, huh? Heh, somthin' tells me that this might be a very interesting timeline."


	3. Start of a Beautiful Friendship

**Summary for the Chapter:**

> Reader and Sans finally meet.

As I stood in front of the Ruins door I let out a small sigh before sittin' on the ground with my back against the door and knocked on it with my one boney knuckle.

"Knock knock," I added while knocking.

" Who's there?" A sweet voice questioned from behind the door.

I slightly stiffen as the glowin' white pupils from my eyes disappeared. That wasn't Tori's voice this, of course, made me worried. 

What if she was already dead? What if this was Chara talkin' ta' me right now?

"Hello? Are you still there?" the voice asked with a small disappointed sigh.

" I probably scare you off,"

"Laney?" I heard Tori's voice question in slight anger.

" What are you doing down here?" She questioned with her voice in a very strict tone.

I let out a small sigh of relief. Tori was still alive wait.....did she just say that the owner of that voice was Laney? I stay quiet to listen into the conversation a little more.

"....I'm sorry momster it just I heard you telling knock-knock jokes with someone on the other side one day and I was just curious," Laney responded in a sad tone.

That had placed guilt in my soul. She was just tryin' ta' find someone to talk ta'. Being locked up in the Ruins can get lonely sure she had Tori, Frisk, and this Sal but sometimes you need more than just three people to talk ta'.

" My child you know that you are not supposed to be down here. And what if that was one of the guards looking for humans?" Tori added now sounding more upset.

That was when I knew I had to speak up.

" Uh~ eya' lady don't blame the kiddo over there I just got lonely and needed to tell jokes ta' someone since you were unavailable," I spoke while shrugging against the door.

"Oh I see ..please don't tell anyone, my friend, she and her sisters very dear to me,"

" Nah, I kinda like the kid so your secret is mine...ey' do you mind if I talk to the er' a little longer? I was kinda havin' a good time with her."

"Of course Laney I will call you when dinner is ready." She added as her voice slowly becomes distant. Once I was sure that she was gone I had decided to finally speak up.

" So..."

" You're Sans aren't you?"

"How..?"

" Frisk had told me everything after meeting Toriel... and don't worry it was just her and me Sal was with Momster during our sister talk."

" Frisk told you huh?"

" Yes and Sans?"

"Yeah?"

" I'm sorry for everything the resets...Frisk killing your brother I...I know my apology won't be enough....it must be a lonely nightmare to be gose through that by your self."

"I have ta' admit it is pretty Bonely," I responded with a small shrug earning a small snort from Laney.

" Frisk had told me that you were a very Punny skeleton I didn't think the pun part was true."

" Yeah well. livin' in a world like this I have to survive somehow." I said while closin' my eye sockets as I let out a low chuckle.

For some reason the more I talked to the kid I felt more comfortable around er' it was as if the Devotion from her soul was flowing thru the door towards mine letting me know that as a new friend she wouldn't let me down in any way.

But I couldn't trust er' not yet I had ta' know a little more about her and Frisk about their past maybe it can help me find out. Why the kid offered that demon their soul so easily.

" Uh~ so what about you?"

" Me?"

" Yea', What made you decide to fall down the Rabbit hole?"

"...."

" Come, pal, you know mine and Frisk's little secret at least give me somthin' about yours and hers," I said and waited thru a long pause of silence.

" You still there?"

" Our dad."

" Your dad? What about your old man?"

".... He was about to rape Frisk," she responded with her voice slightly shaking.

I stiffen slightly against the door maybe I shouldn't have asked or at least waited until after future visits.

" Ey'....look kiddo you don't have ta'..."

" No, I do I know about your's and Frisk's story. And since Frisk and I had decided that whenever Momster lets us out we were going to search for you to stop that horrible cycle with all four of us working together. I think that you should know about ours ....it's only fair." She responded with a small sigh.

She was right it was fair with er' knowing about what was happening and us workin' together in the near future. Of course, I could always wait till they were out of the ruins but neither of us knew when that was goin' ta' happen.

So it was now or never. 

But I couldn't let her be alone in there when she tells their story it ain't right ta' let a girl cry on their own especially when that girl was actually growin' on me. But kinda figured that would happen since the other me made me promise ta' protect er' even though we both hated makin' promises.

" A'right, but before we begin I'm goin' ta' do somthin' that you can't tell your mom about. Capiche?" I asked while standing from the ground as I dust myself off.

"What are you...?" Before Laney could finish she finds me standing in front of her after a small popping sound fills the room.

She looks up at me in shock as I look down towards er'. I couldn't take my eyes off of her stars she was just..to beautiful.

There in front of me, Laney was sitting on the ground with her back against the door. Wearing a dress that looks like it was made from a large pink and white lotus flower trimmed with black lacing. Her long soft brown hair was braided into two long pigtails with a white and black bow on each side. As for her soft blue eyes, they sparkled in the dimly lited room like starlight.

Now I knew why my soul was calling for hers it was not friendship it was more much more. Of course, I already knew what the true reason was I was just being a stubborn bonehead to admit it. 

This also meant that I was going ta' have a little chat with the other me later but until then I had something more important ta' attend to.

"Eya' Sweet eart'," I said with a low chuckle towards Laney's adorable shocked expression.

" How?"

" I took a shortcut I'm sure that Frisk told you about em', But uh~ lets keep this a secret from your Momster we don't want er' ta' find out and stop my visits. Now, do we?" I finished as I place my finger against my permanent smile as I give er' a small wink.

Earning a small head nod in agreement from Lanes as she blushes softly while gently biting her lower lip.

" Good now then Lanester I think you have a story ta' tell me," I added while sitting next to her on the stone ground as I lean against the metal door once more.


	4. Meeting The Family

**Summary for the Chapter:**

> Sans learns about Frisk's father and meets Toriel again

" During Frisk's birth, our mother had passed away. And my father had started to put the whole blame on my little sister even if she was just a baby who had just entered the world. And so he had become abusive towards her physically and mentally. Dad must have thought that I would have been okay with it but I wasn't I mean Frisk was my flesh and blood I love her so I tried to stop him, of course, this made him angry so I got the physical beatings instead of Frisk. Along with his anger and depression came the drugs and alcohol which took a lot of the money for our food and home. So I started a part-time job that allowed me to work after school while Sal had started babysitting Frisk to make sure our dad couldn't hurt her. Then..on the day we fell down here dad was really high to where he ...wanted to teach Frisk a lesson in his room so ...I knock him out then we ran off with Sally..and now here we are." Laney finishes with a soft whisper as she looks down towards her hands in an attempt to hold back her tears.

I stiffen in anger as my glowing pupils vanish having nothing but darkness in my eye sockets.

No wonder the kid allow that demon to join her soul she was scared probably running from her Pops while Laney was stopping im' and Chara along with the Weed took advantage of that. The thought of their dad beating the fuck out of Laney only filled me with anger even more.

That must of been one of the main reasons Chara had always convinced Frisk to do the restarts so many times. The kiddo just had gotten lucky this time as the last restart had landed them before the fall.

How could someone like that not be judged for their actions? There are so many signs of abuse and yet no one noticed or just ignored it... if they had lived down ere' I would have given the old man the judgment he deserved.

" Sans? " I heard a soft voice whisper as a gentle warm hand was placed over mine.

My eyes quickly return back to normal I was afraid that I was scaring Laney.

" Heh, sorry about that sweet eart'," I responded with a low chuckle as I place my hand over hers.

" It's just you have some history in the head of your's," I added as I raise my free hand and gently tap her forehead with my boney finger.

" I have ta' say I'm glad that you and the kiddo are ere' and safe. "

" So am I we have an amazing mother now and...I got to meet you," she added with a sweet smile as her eyes locked with mine.

I don't know how long we were sitting like that for but we suddenly jumped as the sound of a throat clearing fills the room.

We quickly look towards the sound finding Tori standing there with Frisk peeking out from behind her giggling softly.

Toriel, on the other hand, look like a mother lion about to attack the one who had tried to hurt her cub.

Seeing this I knew that I had to do somethin'.

"Uh~ Look I'm sorry it's just her voice was so Adoorable that I just had ta' see the door lady's daughter." I finished with a wink as I thumb towards the large iron door.

Tori only glares down at us for a few more minutes having Laney and me stiffen in worry.

She must have been watching our souls seeing how they were reacting to each other because after a few minutes of that cold glare she shuts her eyes and lets out a small sigh.

" I see ..may I ask how you got in here my friend?"

"Eh, I have few short cuts here and there don't worry I'm the Bonly one who can use them." I finished earning a soft giggle from Toriel as Frisk smile at Lanes and me from behind er'.

" I'm Sans, Sans the Skeleton by the way," I added while holding out my hand towards her after standing from the ground.

" Toriel." She responded with a sweet smile as she takes my hand and gently shakes it.

" Will you like to stay for dinner Sans? I am sure that their sister Sally would like to meet you."

" I would love to but uh, I have ta' head back to my station before my bro gets upset," I responded with a shake of my head while placing my hands in my pockets as I give her a small lazy shrug.

" I see well then please do visit more ofter it is nice to have a guest from outside."

" Sure thing Tor, see ya' tomorrow kiddo. " I added with a wink towards Laney before teleporting away.

" Brother there you are! Why did you leave you Station?!"

" Sorry Paps I went to visit an old friend." I responded as I walk up to my station where Papyrus was waiting.

"..Normally I would be upset at you for leaving brother but...you seem happier toady!"

" Do I? Heh, I guess the visit was just that Bonerrific." I finisned with a wink earning a loud annoyed. Nyeh! From my younger brother.

Everything was going perfect I met Laney, Frisk's soul doesn't seem to have Chara in it, and Toriel had invited me to visit whenever I wanted. Yeah, everything was perfect....maybe a little to perfect.


End file.
